Vehicle Mass-Based Breakpoint for Transmission Shift Schedules
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Solution Overview
Problem
Current motor vehicle transmission systems lack an efficient method to automatically determine and adjust between economy and performance shift schedules based on vehicle mass, leading to suboptimal fuel efficiency and performance.
Innovation Solution
A method and system that compute a vehicle mass-based shift schedule breakpoint by determining the cumulative net tractive force and change in vehicle speed, comparing it to a current vehicle mass indicator, and selecting between economy and performance mode shift schedules to control transmission shifting accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single pre-programmed shift schedule is used, then the control system is simple, but fuel efficiency and performance are suboptimal under varying vehicle mass conditions
Solution Approach 1:
The patent implements dynamic shift schedule selection by computing a mass-based breakpoint in real-time and automatically switching between economy and performance schedules based on current vehicle mass relative to the breakpoint. This makes the control system adaptive to varying vehicle mass conditions rather than static
Solution Approach 2:
The patent changes the control parameter from a fixed shift schedule to a dynamically computed mass-based breakpoint that divides the operating range. The breakpoint is calculated based on vehicle mass, and this parameter drives the selection between two shift schedules, enabling adaptability without requiring a completely complex new control architecture
2Ease of operation
If manual selection of shift schedule is required, then system complexity is reduced, but ease of operation deteriorates
Solution Approach 1:
The control circuit performs self-service by automatically determining the vehicle mass-based breakpoint and selecting the appropriate shift schedule without driver intervention. The system monitors vehicle mass, computes the breakpoint, and autonomously switches between economy and performance schedules based on current operating conditions
Solution Approach 2:
The system uses feedback from vehicle mass sensors to continuously monitor actual vehicle mass and compare it against the computed breakpoint. This feedback loop enables automatic adjustment of shift schedule selection, with the control circuit responding to mass changes by switching schedules appropriately
3Use of energy by moving object
If vehicle mass-based breakpoint computation is implemented, then fuel efficiency improves, but computational requirements increase
Solution Approach 1:
The patent performs preliminary computation of the mass-based breakpoint during vehicle configuration or initialization, storing it for later use. This preliminary action avoids the need for complex real-time computations during operation, reducing computational requirements while still enabling fuel-efficient operation
Solution Approach 2:
The patent segments the vehicle mass range into two regions divided by the mass-based breakpoint, with each region associated with a specific shift schedule. This segmentation simplifies the control logic to a simple comparison operation rather than requiring complex continuous optimization computations
Data Source
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AI summary
A method is provided for selecting between economy mode and performance mode shift schedules for a transmission in a motor vehicle. A desired vehicle acceleration profile is specified, and a cumulative net tractive force of the vehicle is determined over the desired vehicle acceleration profile. A change in vehicle speed over the desired vehicle acceleration profile is also determined. A vehicle massbased shift schedule breakpoint is computed as a function of the cumulative net tractive force of the vehicle and the change in vehicle speed over the desired vehicle acceleration profile. The vehicle mass-based shift schedule breakpoint is compared to a current vehicle mass indicator, and one of the economy mode and performance mode shift schedules is selected for operation of the transmission based on the comparison. Shifting between gear ranges of the transmission is controlled using the selected one of the economy mode and performance mode shift schedules.